1. Field of the Invention
This invention relates to a device for adjustably leveling a material capable of being doctored, such as a wet, fluid thermal-insulating concrete composition after it has been applied to a surface.
2. Description of the Prior Art
Lightweight thermal-insulating concretes are used as thermal-insulating layers in roofs, etc., of buildings and the like. Such compositions, which are typically mixtures of essentially cement binder, lightweight aggregate such as expanded vermiculite or perlite, and water, are usually mixed at the job-site and pumped to the rooftop, etc., of the building. The compositions are highly fluid and have the consistency somewhat of "shaving cream" when cast on the roof deck. One comerically popular roofing system using layers of such insulating concretes is described and shown in U.S. Pat. No. 4,189,886 to Frohlich et al.
When the light, highly fluid insulating concrete has been applied to a roof deck surface, one way to obtain the desired height of the concrete coating is to place rails on each side of the area being coated. The height of each rail is the height of the desired coating. Then a bar or board called a screed bar is pulled along the top of these two rails to level by doctoring the material so that the final coating obtained is the desired height. The problem with this technique is that it is then necessary to have a workman step into the area that has just been coated, remove the rails, fill in the empty space left by the rails with the coating material and as the workman backtracts to also fill in his footprints. A further disadvantage of this technique is that since the thickness of the material being poured at any location may vary, it is necessary to carry to the job site rails of different thickness and these rails can easily be misplaced or damaged while moving from job to job in the back of a truck.
3. Objects of the Invention
It is an object of this invention to have an adjustable doctoring device that will ride on the surface being coated and which has a doctor board or screed bar that is completely adjustable to any desired height.
It is a further object of this invention to have an adjustable doctoring device that is supported by two narrow skid runners which ride on the surface being coated so that as the device is pulled through a wet material being applied (such as lightweight insulating concrete), the narrow track openings made by the runners can be filled in by the material itself.
It is a further object of this invention to have an adjustable screed bar support assembly in the form of a shaft with a sled runner at one end and an adjustable screed bar bracket on the shaft which can move up and down the shaft to any locked positions and in which the shaft will not rotate with respect to the bracket and sled runner.
These and further objects will become apparent as the description of the invention proceeds.